Sintering process and apparatus for producing hard pellets



A. HUBER March 21, 1961 SINTERING PROCESS AND APPARATUS FOR PRODUCING HARD PELLETS Filed Dec. 2, 1957 Inn/anion ADA M H u 13 E R W MLMM+ Hm ATTORN E YS United States Patent 9 SINTERING PROCESS AND APPARATUS FOR PRODUClNG HARD PELLETE Adam Huber, Offenbach (Main), Germany, assignor to Metallgesellschaft Aktiengesellschaft, Frankfurt am Main, Germany Filed Dec. 2, 1957, Ser. No. 700,030

Claims priority, application Germany Jan. 8, 1957 Claims. (Cl. 266-21) This invention relates to the sintering of pellets. In particular, the invention is directed to the production of hard pellets by sintering them.

In a sintering apparatus, the material to be sintered is placed upon a grate, and the material sintered by drawing hot gas through the grate and material, or by burning the material while drawing combustion gases through it. Very high temperatures occur in order to hard burn material composed of preformed pellets, and consequently the grate becomes very highly heated.

According to this invention, the grate bars are supported by hollow beams through which cooling gases, such as air, are forced, while the grate bars themselves are not directly cooled.

The supporting beams of this invention are strengthened by inserting reinforcing beams in them. As the reinforcing beam is washed with cooling gas, it remains cooler than the surrounding supporting beam and thus retains the essential portion of its cold solid strength. It, therefore, is possible to either make the supporting beam of weaker construction, or to make it carry a heavier load.

The means for producing the invention are described more fully with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view through a sintering grate according to this invention;

Figure 2 is a cross-sectional view on the line A--A' of Figure 1; and

Figure 3 is a cross-sectional view similar to Figure 1 of a modified form of the invention.

As shown in Figures 1 and 2, the material 5 in the form of pellets to be sintered rests on grate 6 in a sintering pan. Supporting beams 7 are hollow and carry an upwardly extending T-shaped flange 9 to which the grate bars 6 are fitted. Inserted longitudinally co-extensive with and through each support beam 7 is a reinforcing beam 12 which is held by bearings '13 at each end. These bearings are pressed into the thick side walls of supporting beam 7. An intake air opening 15 is positioned in the lower side of one bearing and an exhaust air opening 16 positioned in the upper side of the opposite 2,976,029 Patented Mar. 21, 1961 2 bearing. This arrangement allows a natural rising of heated air and thus increases the cooling draft.

Lugs 17 formed on the inner side of the top wall of supporting beam 7 provide additional support for the supporting beam by bearing with almost point-like contact upon reinforcing beam 12. This point-like contact keeps the direct heat transfer from the supporting beam to the reinforcing beam to a very small degree.

The lugs 17 can be similarly mounted upon beam 12. The heat transfer is further reduced by inserting insulation layers 18 composed of a common material such as asbestos between the lugs 17 and the adjacent beam.

In the modification shown in Figure 3, the reinforcing beam 12a is made hollow and has cooling air passed therethrough.

Having now described the means by which the objects of the invention are obtained, I claim: 1

l. A forced draft sintering grate for sintering hard materials at high temperatures comprising grate bars, supporting beams carrying said bars, said supporting beams being entirely closed on their longitudinal tops, bottoms and sides and having an opening at each longitudinal end for the passage of cooling gas therethrough, and a reinforcing beam longitudinally and substantially co-extensively mounted within each supporting beam with the outer end portions of each reinforcing beam bearing in the inner end portions of its respective supporting beam, and said reinforcing beam being spaced from and entirely enclosed by said supporting beam to form an air cooling passageway longitudinally through said supporting beam from one open end to the opposite open end thereof.

2. A sintering grate as in claim 1, further comprising point-like bearing contacts between the reinforcing and supporting beams.

3. A sintering grate as in claim 2, said contacts comprising lugs.

4. A sintering grate as in claim 3, further comprising an insulating layer between each lug and its adjacent beam.

5. A sintering grate as in claim 4, further comprising a hollow cooling air passageway in said reinforcing beam.

References Cited in the file of this patent UNITED STATES PATENTS 828,769 Parkison Aug. 14, 1906 890,552 Bibb June 9, 1908 1,329,447 Van Brunt Feb. 3, 1920 1,742,908 Gibson Ian. 7, 1930 1,888,348 Hegeler Nov. 22, 1932 2,569,438 Batik Oct. 2, 1951 2,675,223 Rolfsen Apr. 13, 1954 2,708,107 Holcroft et al. May 10, 1955 2,862,308 Meredith et al. Dec. 2, 1958 FOREIGN PATENTS 753,570 Great Britain July 25, 1956 

